AuthorTopic: No power to Ecm (Read 118 times)

Not getting any power to the ECM with the key on. So tested for power using a test light to vpower on the diagnostic connector to the positive battery terminal. When I did that the ECM powered up. Though the test light was dimly flashing. The check engine light was on as well with the key on. But when I disconnected to the test light the check engine light went out. Also I did check the vpower connector at the ECM unplugged of course. With a test light at a good ground koeoff no power from that wire. Also the keep alive wire had power to it like it should. Any ideas as to where to start to test first. And I've already installed a new ignition switch thinking that was the problem.

Also all fuses tested good. None have popped. I cleaned all of the main wiring harness connectors with a industrial electric connector cleaner. And what is the real hair pulling for me. Is all I did was install a new clutch and that is when this problem happened.

Has anyone else have this happen to them and what was the underlying cause?

Sounds like an issue related to the main injection relay located on the driverside fender wall.

Coming out of this relay will be a short pigtail with a round 6 pin plug. With your test light, check for voltage on two blue wires. These go to the injection fuse and should have voltage.

Next turn the ignition switch on and test the black/white wire's pin(ignition switch) for voltage, it's next to the black wire pin(ground). Also verify the ground wire is good. These wires turn the relay on.

On the opposite corner of the plug will be another black/white wire and a yellow/green wire(relay outputs). When the relay is on, both of these should have voltage then too.

The yellow/green wire from the relay turns the ecm on and the black/white wire turns the distributor on.

Update. Found the problem. It ended up being a single power wire in the 3 pin green connector. The terminal decayed into dust when it got moved around during the clutch replacement. To everyone who replied to this thread THANK YOU VERY MUCH.